GClocks

Interval Timer

HIIT & Tabata timer with voice coach, presets, custom circuits and shareable links.

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      HIIT · Tabata · EMOM

      An interval timer that coaches you through every round

      Set your work and rest periods, pick a preset or build a full circuit, then put the phone down. The whole screen changes color with each phase, a voice calls out what's next, and every beep lands on time - even with the screen locked.

      How it works

      1. 01

        Pick or build

        Start from Tabata, HIIT, EMOM or Boxing, or set work, rest, rounds and sets yourself. Advanced mode lets you build named circuits.

      2. 02

        Press start

        A 10-second get-ready countdown gives you time to get in position. Colors, voice and beeps take over from there.

      3. 03

        Finish strong

        See your total, work and rest time, keep your daily streak and share the workout with a link or QR code.

      Popular interval formats

      Tabata 20s / 10s × 8

      Four minutes of all-out effort: 20 seconds hard, 10 seconds rest, eight times. Short, brutal and very effective for conditioning.

      HIIT 40s / 20s

      High-intensity intervals with a 2:1 work-to-rest ratio. Great for beginners (30/30) up to advanced athletes (45/15).

      EMOM 60s × N

      Every Minute On the Minute: do a set number of reps at the start of each minute and rest for whatever time is left.

      AMRAP 12:00

      As Many Rounds As Possible in a fixed time. One long work block - just keep moving and count your rounds.

      Boxing rounds 3:00 / 1:00

      Classic fight rounds for bag work, shadow boxing or sparring: three minutes on, one minute rest.

      4×4 intervals 4:00 / 3:00 × 4

      The Norwegian cardio protocol: four minutes at 85-95% max heart rate with three-minute active recovery.

      Why this interval timer

      • Readable from across the room

        Huge numbers and full-screen colors for each phase - red to work, green to rest - so you never squint mid-set.

      • Voice coach

        Calls out each exercise, what's next, halfway and the last round - in your language when your device supports it.

      • Accurate in the background

        Beeps are scheduled on the audio clock, so they stay on time with the screen locked or the tab in the background.

      • Build real circuits

        Named exercises, repeat groups, warm-up and cool-down - drag to reorder and see the total time instantly.

      • Share with a link

        Coaches can send a whole workout as a link or QR code. It opens ready to start - no sign-up, no app.

      • Streaks and history

        Track workouts, minutes this week and your daily streak, all stored privately on your device.

      Frequently asked questions

      An interval timer alternates between work and rest periods automatically and signals each change, so you can focus on the exercise instead of watching a clock. It's used for HIIT, Tabata, circuit training, running intervals and boxing.

      Tabata is 20 seconds of maximum effort followed by 10 seconds of rest, repeated 8 times for a total of 4 minutes. Choose the Tabata preset and press Start.

      Beginners usually start with 1:1 (30s/30s). As fitness improves, move to 2:1 (40s/20s) or 3:1 (45s/15s). For heavy strength work or sprints, longer rest such as 1:2 helps you keep quality high.

      Yes. The screen is kept awake while the timer runs on supported browsers, and beeps are pre-scheduled on the audio clock so they stay accurate even if you switch apps or lock the phone.

      The voice uses the speech voices installed on your device. If there is no voice for your language, it falls back to English. You can add voices in your phone or computer's language settings.

      Tap Share to get a link and QR code. The whole workout is stored in the link itself, so anyone who opens it sees the same intervals ready to start - no account needed.

      Saved workouts, settings and history are stored in your browser on this device only. Nothing is uploaded to our servers.

      On a computer use Space to start or pause, arrow keys to skip, F for full screen and M to mute. On phones you can tap the big number to pause and swipe left or right to skip, and headphone/lock-screen controls work too.